The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The motorization assemblies with a turbojet engine for aircraft include a nacelle forming a generally circular outer envelope, comprising thereinside a turbojet engine disposed along the longitudinal axis of this nacelle.
The turbojet engine receives fresh air coming from the upstream or front side, and discharges, on the downstream or rear side, hot gases resulting from the combustion of fuel, which provide a certain thrust. For bypass turbojet engines, fan blades disposed around the motor generate a significant secondary cold air flow along an an annular flow path passing between this motor and the nacelle, which generates a high thrust.
Some nacelles include a thrust reverser system which closes at least partially the cold air annular flow path, and discharges the secondary flow forwards in order to generate a braking reverse thrust of the aircraft.
A known type of thrust reverser, presented in particular by the document FR-A1-2758161, includes rear movable cowls axially sliding downstream under the effect of cylinders, while deploying flaps in the annular flow path in order to close this flow path at least partially. These flaps return the cold air flow radially outwards while passing through uncovered cascades during the sliding, comprising blades which direct this flow forwards.
Moreover, the wings of some aircrafts include movable leading edge slats which are deployed forwards and downwards in order to modify the aerodynamic characteristics of these wings, in particular when flying at low speed during landing.
In this case, in particular for nacelles with a large diameter disposed close to the wings in order to keep a sufficient ground clearance below, it is possible to obtain an interference between the deployed movable leading edge slat, and the movable cowls when they move backwards in order to implement the thrust reverser.
In order to avoid this interference, a known type of nacelle, presented in particular by the documents FR-A1-2968635 and EP-A2-2620627, includes at each side of the vertical mast (pylon) maintaining the nacelle, in the area close to the leading edge of the wing located on the top of this nacelle, a small fixed cowl which completes the movable cowl so as to close the entire annular surrounding of the nacelle. In this case, as the small fixed cowl does not move backwards during the opening of the cowl, the risk of interference with the movable leading edge slat is eliminated.
Nevertheless, as these two fixed cowls do not open, they reduce the air flow over the angular sector that they cover during the thrust reversal, and therefore the braking thrust delivered by this thrust reverser.